Why there is too many uneccessary casts?

[Timothee Cour]

On Tue, Jun 11, 2013 at 11:26 AM, H. S. Teoh <hsteoh at quickfur.ath.cx> wrote:

> On Tue, Jun 11, 2013 at 01:25:24PM -0400, Steven Schveighoffer wrote:
> > On Tue, 11 Jun 2013 12:18:52 -0400, Adam D. Ruppe
> > <destructionator at gmail.com> wrote:
> >
> > >On Tuesday, 11 June 2013 at 16:05:30 UTC, Steven Schveighoffer wrote:
> > >>CPU performs math at int level.
> > >
> > >eh, I wouldn't blame the hardware. You can do
> > >
> > >asm {
> > >   mov AL, 10;
> > >   add AL, 5;
> > >}
> > >
> > >and it is allowed, it also don't spill into AH if you overflow it
> > >(it just sets the carry flag). I'm sure it is different on
> > >different processors, but x86 is pretty flexible.
> >
> > Well, that is not what I knew, so good lesson :)
> >
> > But I'd be surprised if the above was less costly than a full word
> > addition.  I think that is the point of C's policy of integer
> > promotion, which D adopts for the most part (although C allows it to
> > go back into whatever).
>
> It may or may not be less costly as full-word addition, but it
> definitely allows the optimizer more wiggle room, because it allows more
> byte-sized values to fit into registers before spilling over to memory
> accesses.
>
> But that doesn't really pertain to this discussion. :-P
>
>
> > >>ubyte c = k;
> > >>c += 1; // ok
> > >>
> > >>This I find extremely inconsistent...
> > >
> > >I'd be extremely annoyed if that required a cast. It's bleeding
> > >obvious that you want it to assign back there....
> >
> > I argue the consistency is both ways :)  I don't want to require a
> > cast there (and in reality, where would the cast go?), but it seems
> > that if you are doing math among bytes, or a byte and an integer
> > that can fit into a byte, it should be quite obvious that you are
> > working in the byte land.  The fact that
> >
> > k += 1;
> >
> > and
> >
> > k = k + 1;
> >
> > are treated differently is annoying.
>
> Yeah, I agree that is annoyingly inconsistent. I'm sure there are good
> reasons for it -- avoid common overflow bugs, for example, while not
> making regular int arithmetic a pain to work with by requiring casts
> everywhere. But still, it *is* an inconsistency, and it's still
> annoying.
>
>
> T
>
> --
> Ruby is essentially Perl minus Wall.
>

wouldn't it be a better and more consistent idea to implement bearophile's
'Compiler support to implement efficient safe integrals'
http://d.puremagic.com/issues/show_bug.cgi?id=9850 so uint/int etc would
require no cast
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